Plastic food container

ABSTRACT

A thin-walled thermoplastic container which includes identical dish and cover portions, each having a peripherally extending flange for supporting the other when one is placed on the other to form the assembled container. A restraining collar extending from the flange in the direction of the sidewall prevents crosswise displacement in one direction of one portion with respect to the other, while stabilizing posts in the sidewalls prevent such displacement in the opposite direction. Each portion has locking means which coact with the flange of the other and self engage when one portion is forced against the other.

United States Patent Inventor John H. Rump Rockvllle, Conn. Appl. No.877,957 Filed Nov. 19, I969 Patented Nov. I6, I97! AssignecMonnantoComplny St. Louis, Mo.

PLASTIC FOOD CONTAINER 3 Claims, 5 Drawing Figs.

US. Cl 220/4 E. ISO/0.5, 220/60 R, 229/25, 229/22 lnt.Cl ..B65dll/l0,865d 43/ 10 Field of Search 220/4, 4 E, 60 R; ISO/0.5; 229/22, 2.5

References Cited UNITED STATES PATENTS 8/l96l Pease 220/97 F X 3,326,4086/1967 Ringlen 220/60 R 3,5l 1,433 5/l970 Andrews 220/3] S X FOREIGNPATENTS l,559,692 2/l969 France 220/4 E Primary Examiner-George E.Lowrance Attorneys-James C. Logomasini. Michael J. Murphy and Neal E.Willis ABSTRACT: A thin-walled thermoplastic container which includesidentical dish and cover portions, each having a peripherally extendingflange for supporting the other when one is placed on the other to formthe assembled container. A restraining collar extending from the flangein the direction of the sidewall prevents crosswise displacement in onedirection of one portion with respect to the other, while stabilizingposts in the sidewalls prevent such displacement in the oppositedirection. Each portion has locking means which coact with the flange ofthe other and self engage when one portion is forced against the other.

PAIENTEmmv 1s l97| 3 6 20 403 INVENTOR.

JOHN H. RUMP PLASTIC FOOD CONTAINER BACKGROUND OF THE INVENTION Thisinvention relates to containers and more particularly to thermoplasticcontainers of the single use, throwaway variety.

Disposable thermoplastic containers of many different varieties havebeen introduced in the marketplace in recent years for holdingconsumable solid and liquid products. Thus, open topped cups forbeverages dispensable from vending machines have been supplied. Filmoverwrapped trays for meat, fruit, produce, etc. are likewise known.Tubs tightly capped with removable lids for holding cottage cheese,margarine, butter, etc. in hennetic confinement also have been welldeveloped in the art.

Thus far, however, the only known food items dispensable from vendingmachines for consumption as a light lunch, snack, or dessert arerelatively sturdy items such as sand wiches, fruit, etc. which are filmoverwrapped and are of such a consistency such that they will notdisintegrate or undesirably adhere to the fingers of the purchaser onremoving the protective covering. Accordingly, though a market for suchproducts would appear to exist, food items such as pies, cakes with orwithout frosting, filled pastries, etc. which are susceptible todisintegration during handling and are therefore ordinarily consumedwith an eating utensil, have heretofore not appeared in vending machinesbecause of the lack of a suitable inexpensive yet sturdy disposablecontainer for holding such items, both prior to dispensing and duringconsumption by the purchaser.

SUMMARY OF THE INVENTION Now there has been developed a unique containerto fulfill this long felt need.

Accordingly, it is a principal object of this invention to provide astructurally stable, single-use, selfsupporting, two piece, coveredcontainer for holding an appropriate product.

An additional object of this invention is to provide a container of theaforementioned variety adapted for use in vending machines for holdingsingle servings of relatively easily disintegratable food items.

Another object of this invention is to provide a container of theaforementioned variety which may be used as a dish out of which thepurchased item may be consumed.

A further object of this invention is to provide an economical containerof the aforementioned variety which may be readily formed byconventional thermoforming techniques.

An additional object of this invention is to provide a container of theaforementioned variety which is easy to manufacture, convenient toinventory, assemble and fill with an appropriate product and which isvery desirable for use by the consumer.

Other objects of this invention will in part be obvious and will in partappear hereinafter.

These and other objects are accomplished by providing a two-piece,thin-walled container, preferably for holding food items, made of aplastic material capable of being thermoformed, the container comprisingidentical dish and cover portions, each of the dish and cover portionshaving an end wall which is integrally joined at its marginal edge toone end of a sidewall which gradually tapers outwardly away from the endwall, a supporting flange portion extending laterally outwardly at theother end of each sidewall, a restraining collar extending in the samegeneral direction as the sidewall from the outer extremity of the flangeportion, a plurality of inwardly directed stabilizing posts spaced fromeach other and formed in the sidewalls of the cover and dish portions,the stabilizing posts having end sections extending vertically beyondthe flange portion, locking means in the restraining collar of eachidentical dish and cover portion to hold the cover portion vertically inplace on the dish portion, whereby the end sections of the stabilizingposts abut against upper sections of the sidewalls on sliding one of thecover and dish portions transversely in one direction with respect tothe other and the restraining collar abuts against the flange portion onsliding one of the cover and dish portions transversely in the oppositedirection with respect to the other when the cover portion is mounted onthe dish portion such that the flange of the cover portion is supportedon the flange of the dish portion with the end walls of each on oppositesides of the flanges.

BRIEF DESCRIPTION OF THE DRAWINGS In describing the overall invention,reference will be made to the accompanying drawing in which:

FIG. I is a perspective view of one form of the container of theinvention is open position;

FIG. 2 is a plan view of the upper half of the container of FIG. 1;

FIG. 3 is an elevational view of the container portion of FIG. 2;

FIG. 4 is an enlarged sectional view taken at 44 of FIG. I with thecontainer in closed position; and

FIG. 5 is a view similar to FIG. 4 taken at 5-5 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the drawings,wherein identical numerals refer to identical parts, there is shown inFIG. I, a two-piece, transparent, thin-walled food container made of aplastic material capable of being thermoformed, and which is generallyindicated as 10.

In the illustrated embodiment, the overall shape of the container istriangular since this configuration is particularly adapted toaccommodate sliced products such as pies, cakes and the like. Obviouslyalternative contours such as circular, square, rectangular and othermultisided configurations could be used, as long as the shape issymmetrical about either side of an imaginary vertical plane passingthrough the center of the container.

Container 10 comprises dish and cover portions 12, each of which isexactly identical in construction. Each of dish and cover portions 12has an end wall 14 which is integrally joined at its marginal edge toone end of continuous sidewall 16, which, with respect to the lower halfportion in FIG. I, tapers angularly upwardly and outwardly from end wallI4, and, with respect to the upper portion, tapers angularly downwardlyand outwardly from end wall 14. Sidewalls 16 of both cover and dishportions 12 taper outwardly to pennit stacking a plurality of thecontainer halves within each other prior to filling so as to optimizestorage space. Each portion 12 further comprises a planar-orientedsupporting flange portion 18 extending outwardly in a direction parallelor approximately parallel to that of end wall 14 around the periphery ofeach portion 12 at the other end of sidewall 16. End wall 14 andsidewall 16 define a chamber in the lower half portion 12 of containerI0 for holding an appropriate product. Each portion 12 is preferablyperipherally continuous along the full extent of sidewall 16 and endwall 14, being free of any interruptions, ledges, crevices, inaccessiblecomers etc. which could serve as areas of the package within which thecontents could become lodged. This is especially desirable when thecontainer is to hold a food product. Each portion 12 further has arestraining collar 20 extending in the same general direction assidewall 16 and substantially perpendicular to flange portion 18 at itsouter extremity (FIG. 4). Typically, collar 20 may vary about 15 eitherway from being perpendicular to flange portion 18.

As an important phase of the present invention, there is provided ineach half 12 of container I0, a plurality of inwardly directed,stabilizing posts 22 spaced from each other and formed in sidewall 16 ofeach container half 12. Stabilizing posts 22 have end sections 24 (FIG.4) which extend vertically beyond flange portion 18 and which terminateshort of the outer extremity 26 of restraining collar 20 of theparticular container half in which they are situated. In the preferredtriangular embodiment of the drawings, sidewalls 16 comprise sections ofthe cover and dish portions which are angularly related to each other soas to form corners 28, 30 and 32. Stabilizing posts 22 in such aconfiguration are positioned intermediate two of the comer areas, forexample along side 34 (FIG. 2) of the container.

Restraining collar 20 of each identical dish and cover portion 12 haslocking means 36 (FIG. 5) formed therein adapted to resiliently snaparound flange portion 18 of the other half portion to hold the coverportion vertically in place on the dish portion. In the embodiment ofthe drawings, locking means 36 comprises a pair of inwardly curvingU-shaped detents 38 in the same side 34 of the container as are situatedstabilizing posts 22. Detents 38, however, are adjacent to but not inhorizontal alignment with posts 22, since an aligned configurationpresents difficulties in thermoforming because of the problem ofextricating the section of flange portion 18 intermediate such analigned post and detent configuration from the forming mold. Thisdifficulty is caused by the reverse taper of post 22 with respect tosidewall 16 and of detents 38 with respect to collar 20.

As is apparent from FIG. I, when container is in closed position, thecover portion is mounted on the dish portion such that the flange 18 ofthe cover portion is supported on the flange of the dish portion withthe endwalls 14 of each on opposite sides of flanges 18. In such aposition, collar of the lower dish portion extends upwardly so as tosurround the outer end of flange 18 of the upper portion (FIG. 1 whilethe corresponding collar 20 of the upper cover portion extendsdownwardly so as to surround the outer edge of flange portion 18 of thelower portion (FIG. 4). Also, when container 10 is in closed position,end sections 24 of stabilizing posts 22 along one side of the upperportion of the container below flange 18 project into the chamber formedby lower dish portion 12 (FIG. 4) whereas the reverse is true withrespect to the lower portion of the container, i.e. the upper ends ofposts 22 protrude upwardly into the chamber formed by the cover portionof the container. Thus with respect to the configuration of FIG. I, ifthe cover portion should be moved in a planar direction to the right or,conversely, the dish portion moved to the left, for example duringjostling while being closed after filling and/or inserted into a vendingmachine, end portions 24 of stabilizing posts 22 will abut against uppersection 35 of sidewall 16 of dish portion 12. This prevents thethin-walled container from distorting out of shape and maintains coverportion 14 in substantial vertical alignment on lower dish portion 12.If the reverse movement should occur, i.e. the cover portion move to theleft in FIG. 1 or the base portion move to the right, restraining collar20 of the lower portion will abut against the outer edge of flange 18 ofthe upper portion and thereby prevent any further distortional movementof the container. 1

The extent 24 to which each stabilizing post 22 projects into thechamber formed by the opposite portion when the container is in closedposition is greater than the vertical distance 37 (FIG. 5) betweenflange 18 and the upper end of the particular leg 40 of the U-shapeddetent 38 of locking means 36 which is closest to its flange portion 18.Thus, if the cover portion should accidentally be incrementally movedupwardly or the lower portion downwardly a distance indicated as 37 inFIG. 5 during handling, the lower end 24 of each stabilizing post 22will still be beyond the flange portion 18 of the opposite portion, andcan therefore still perform its containerstabilizing function. However,end portion 24 of each stabilizing post 22 should not projectexcessively into the chamber of dish portion 12, since this decreasesthe open volume available for confining the container contents.Preferably the extent to which each stabilizing post 22 protrudes intothe chamber of the other portion when the container is in closedposition in order to accomplish its desired function under allcircumstances is between one-sixteenth to one-fourth inch. In any event,lower end portions 24 should not extend beyond the extremity 26 ofcollar 20 in order to pennit forming the container by conventionalthermoforming techniques.

In the preferred form of the present invention, the container isdesigned to be made by means of a trapped sheet, cut-inplacethermoforming system. Thus, each restraining collar of the dish andcover portions tapers gradually into flange portions 18 along a sectionof the periphery of the container, as indicated at 42. It should beunderstood, however, that alternatively collar 20 could be squared offat its joint with flange portion 18 and need not be of a slopingconfiguration when formed in a post trim thermoforrning system.Likewise, though it is preferred for purposes of container stabilitythat collar 20 extend around only one-half of the periphery of eachportion as shown in the drawings, it should be recognized thatsatisfactory results are attainable when collar 20 extends entirelyaround the periphery of each half portion of the container. In thelatter instance, however, the half portion without the locking meansmust be shorter in the vertical direction than that having the lockingmeans. In other words, with respect to the preferred embodiment, thehalf portion without the locking means may have a short restrainingcollar portion which extends in the vertical direction no greater thanthe distance between flange l8 and the upper end of the leg of theU-shaped detent adjacent flange 18 of the collar portion having lockingmeans 36 therein.

The above description and particularly the drawings are set forth forpurposes of illustration only and are not to be taken in a limitedsense.

The identical dish and cover portions of the novel container of thepresent invention are relatively shallow, having a depth of between 0.5to 3 inches. Thus, when the contents of the container is a food product,this permits easy-access thereto with an eating utensil.

The flange of the dish and cover portions of the container must besufficiently wide to provide adequate support for the other half whenthe container is in its assembled position, yet, in the case of acontainer for use in a vending machine, the flange cannot be so wide asto interfere with the relatively compact compartment within which thecontainer is to be confined after filling. Generally, a width of betweenone thirty-second to three-eighths inch for these portions of thecontainer accomplishes the desired objectives.

The sealing means of the container of the present invention preferablyfunction outside of the recesses formed in the cover and dish portionsin order to avoid contact with the contents thereof, and to permitholding the internal container volume at a minumum in order toeconomically yet effectively confine the contents. In other words, thelocking means of the container coact with the flange portions whichproject outwardly of the interior of the cover and dish portions. Bydesigning the locking means to be self-locking, time to assemble andopen the filled package may be kept at a minimum, with no auxiliarymeans, such as adhesives, sealants, auxiliary clips etc. beingnecessary, these serving to increase the cost of the container and oftenbeing difficult to disengage with out disrupting the contents.

The stabilizing posts of the container of the invention occupy a limitedarea of the container periphery and may vary in number depending on thesize of the container, at least two, however being considered necessary.For most container sizes, between two and six posts in each containerhalf provide acceptable results.

The material from which the container is made is a sy thetic resin sheetcapable of being thermoformed, and particularly a sheet of a materialwhich may be biaxially oriented to impart strength thereto at arelatively low cost per pound. A particularly preferred thermoplastic isbiaxially oriented polystyrene, which in the case of a container forvending machine applications, is transparent for purposes of displayingthe contents. The sheet should be relatively thin before drawing, inorder to be consistent with the intended single-use, disposable,lowcost, variety of container. Thicknesses between 5 to 40 mils providesatisfactory results in terms of container performance. At sheetthicknesses below 5 mils, the formed container generally does not havesufficient strength to be self-supporting in a sufficiently sturdymanner in a vending machine dispensing operation. On the other hand,sheet thicknesses in excess of 40 mils are relatively uneconomical andare rather difficult to draw while still retaining the strengthimparting biaxial orientation in the thermoplastic.

Transparent" as used herein is meant to indicate that the nature of thecontents can be determined by viewing the exterior of the container.This term therefore characterizes a container which permits partial aswell as complete visibility of the contents.

It will be understood that many variations and modifications of theembodiments herein described will be obvious to those skilled in theart, and may be carried out without departing from the spirit and scopeof the invention as hereinafter claimed.

What is claimed is:

l. A two-piece, thin-walled container made of plastic material capableof being thermoformed, said container comprising identical dish andcover portions, said dish and cover portions are triangular inperipheral contour, each of said dish and cover portions having an endwall which is integrally joined at its marginal edge to one end of asidewall which gradually tapers outwardly away from the end wall, asupporting flange portion extending laterally outwardly at the other endof each sidewall, a restraining collar extending from the outerextremity of the flange portion in the same general direction as thesidewall, a plurality of inwardly directed stabilizing posts spaced fromeach other and formed along one side of said triangular contour of saidcover and dish portions, said stabilizing posts having end sectionsextending vertically beyond the flange portion, locking means in therestraining collar of each identical dish and cover portion for holdingthe cover portion vertically in place on the dish portion, saidrestraining collar extending only one-half way around the peripheryincluding the peripheral sections of the dish and cover portions inwhich the stabilizing posts are located, whereby said end sections ofthe stabilizing posts abut against upper sections of the sidewalls onsliding one of said cover and dish portions transversely in onedirection with respect to the other and said restraining collar abutsagainst said flange portion on sliding one of said cover and dishportions transversely in the opposite direction with respect to theother when said cover portion is mounted on said dish portion such thatthe flange of the cover portion is supported on the flange of the dishportion with the end walls of each on opposite sides of said flanges.

2. The container of claim I wherein the plastic material is transparent,oriented polystyrene.

3. The container of claim I wherein each end of the restraining collarat its joint with the supporting flange portion tapers gradually intosaid flange portion along a section of the periphery of the container.

1. A two-piece, thin-walled container made of plastic material capableof being thermoformed, said container comprising identical dish andcover portions, said dish and cover portions are triangular inperipheral contour, each of said dish and cover portions having an endwall which is integrally joined at its marginal edge to one end of asidewall which gradually tapers outwardly away from the end wall, asupporting flange portion extending laterally outwardly at the other endof each sidewall, a restraining collar extending from the outerextremity of the flange portion in the same general direction as thesidewall, a plurality of inwardly directed stabilizing posts spaced fromeach other and formed along one side of said triangular contour of saidcover and dish portions, said stabilizing posts having end sectionsextending vertically beyond the flange portion, locking means in therestraining collar of each identical dish and cover portion for holdingthe cover portion vertically in place on the dish portion, saidrestraining collar extending only one-half way around the peripheryincluding the peripheral sections of the dish and cover portions inwhich the stabilizing posts are located, whereby said end sections ofthe stabilizing posts abut against upper sections of the sidewalls onsliding one of said cover and dish portions transversely in onedirection with respect to the other and said restraining collar abutsagainst said flange portion on sliding one of said coVer and dishportions transversely in the opposite direction with respect to theother when said cover portion is mounted on said dish portion such thatthe flange of the cover portion is supported on the flange of the dishportion with the end walls of each on opposite sides of said flanges. 2.The container of claim 1 wherein the plastic material is transparent,oriented polystyrene.
 3. The container of claim 1 wherein each end ofthe restraining collar at its joint with the supporting flange portiontapers gradually into said flange portion along a section of theperiphery of the container.